Navigation instrument



June 24, 1941 D. G. LUCK v I I A'2,247,029

NAVIGATION vINS TRUMENT Filed Jan, 5l, 1939 3 Sheets-Sheet 1 WM.Bil-SING .SPH/NG CHM F'OLLDWER 107 Non Impr P1 G. 3H. l 111 Q03 .DavidGllLucfi `101 4 5ms/1v@ .swr/NG 105 8v BH4/rf:

Gtorpeg 5 Sheets-Sheet 2 (Ittorneg David G. C. L

D. G. c. LUCK l NAVIGATION INSTRUMENT Filed Jan. 5l, 1939 hmwmwmmwm l Lnu Ilm l June 24, 1941.

June 24, 1941. n. G. c. LUCK NAVIGATION INSTRUMENT Filed Jan. 31, 1959 ssheets-shea s Buventor DavidV G.C.L uch', Mttern@ Patented June 24, 1941NAVIGATION INSTRUMENT David G. C. Luck, Oaklyn, N. J., assignor to RadioCorporation of America, a corporation of Dela- Ware Application January31, 1939, lSerial No. 253,890

(Cl. Z50-11) Claims.

This invention relates to navigation instruments and, more particularly,to an instrument in which radio headings and earth compass headings arecombined to indicate a radio bearing with respect to a meridian. Theinventionfurther contemplates the use of crossed pointers on a map toindicate position as a function of two radio bearings.

If an earth compass of the magnetic, earth inductor or gyroscopic typeis used on a mobile vehicle, the compass will indicate the heading ofthe vehicle with respect to the meridian. If a radio compass is used, itwill indicate a line, with respect to an axis of the vehicle, on which aradio transmitter is located. If the radio compass has sense, it willindicate not only the line along which the radio station is located, butthe sense of direction of the transmitter. If the radio bearing of thevehicle with reference to a meridian line be required, it is necessaryto add `algebraically the radio compass indication and the earth compassindication.

If position is to be determined, it is customary to use two or morebearings. The intersection of two bearings will indicate position. Ithas been proposed to employ a pair of crossed indicaters on a map. Theaxes about which the indicators rotate are made to correspondrespectively to the locations of a pair of radio transmitters. Thebearings obtained by radio are indicated by the pointers and theirintersection indicates position. When such a device is stationary, themeans for operating thepointers may be relatively simple. If the rnapinstallation is used on a vehicle which may be continuously changing itsheading, it becomes necessary to make corresponding changes in theorientation of the map or both pointers. The means previously employedto either orient the map or the pointers have been complex.

It is an object of the present invention to provide relatively simplemeans for electing true bearing or position indications on a mobilevehicle.

Another object is to provide means for obtaining radio bearings relatedto a meridian.

Another object is to provide means for combining the indications of aradio compass and an earth compass to obtain radio bearings related to ameridian.

A further object is to provide means for obtaining a pair of bearings bycombining radio and earth compass indications.

A still further object is to provide means for indicating position on amap by applying automatically indications of bearings obtained by radio.

The invention will be described by referring to the accompanyingdrawings in which- Figure 1 is a diagrammatic presentation oi thenavigational problem to be solved.

Figure 2 is a schematic representation of one embodiment of theinvention,

Figures 3A and 3B are side and elevational views of an element of theinvention,

Figure 4 is a plan View representing a position indicator,

Figure 5 represents another embodiment of the invention, and

Figure 6 represents a modification of the arrangement represented byFig. 5.

Referring to Fig. 1, the operator of an airplane l flying a course 3obtains its earth heading H", in terms of angular departure from thenorthsouth meridian line 5, by means of an earth compass. By means ofradio compass, a radio heading R is obtained from a radio transmitterlocated at the point 'l on a meridian line 9. The actual bearing of theaircraft from the radio transmitter, with respect to the meridian line,is 13 which may be determined from the equation The foregoing problem innavigation may be solved by combining, automatically, bearing indicationfrom the radio and earth Compasses, as will be explained by reference toFig. 2. A radio compass receiver l is connected to an antenna 3 and aloop 5. The connections from the loop are reversed in synchronism withthe connections to a differential relay 'l by means of motor 9 drivenswitches Il, I3. The movable terminal I5 of the differential relay isconnected to one phase of a pulse generator l1. One fixed terminal I9 ofthe differential relay is connected to the forward windings 23, 25 of apair of motors 2l, 29. The other terminal 2| is connected to the reversewindings 3|, 33 of the motors. These motors are preferably of theimpulse driven type including a ratchet, or its equivalent, topositively position the armatures. The first motor 21 is connected by ashaft 35 to the loop 5 for orienting the loop. The second motor 29 is aheading repeater motor whose function will be described hereinafter.

An earth compass 31, of the gyro or other suitable type, is connected toa repeater device mechanism 39 which, for example, may be of the typedisclosed in Figs. 3 and 4 of U. S. Patent 2,080,511, granted` May 18,1937. The output of vcaused to engage a cam follower |39.

the repeater device is connected to a second differential relay 4|. Thefixed terminal 43 of the second differential relay 4| is connected to asecond phase of the pulse generator circuit. One of the fixed terminals45 of the differential relay is connected to the forward windings 41, 43of a pair of impulse motors 5I, 53. The other fixed terminal 55 of thesecond differential relay is connected to the reverse windings 51, 59 ofthe motors 5|, 53. The first of these motors 5| is a servo motor,coupled by a shaft 3| to the follow-up or repeater mechanism 39. Thefollow-up device 39 m-ay be any one of the types well known in the art.It must, however, exert no reaction on the compass proper.

The field windings of the four motors 21, 29, 5|, 53 are connected inseries parallel to the field windings of a third repeater motor 63. Thefield windings, forward and reverse, of the third repeater motor areconnected in series with corresponding field windings of two bearingindicating motors 65, 61. The terminals of the final pair of eldwindings are c-onnected to ground to provide a return path to the pulsegenerator circuit.

The motors 35, 51 are connected, respectively, to clutches '69, 1|. rFheclutches will be hereinafter described. They are energized by solenoidwindings 13, which are connected toground and to` .terminals 11, 'I5 ofa synchronously operated switch 3|. The switch may be operated by amoto-r 83. The other fixed terminals 35, 81 of the switch 8| areconnected to tuning elements 3| which are connected to the radioreceiver The movable contact of the switch is connected to groundthrough a battery 53 which energizes the clutch windings 13, 15. IThebattery is ley-passed for radio frequency currents.

The bearing motors 65, 61 are engaged to and disengaged from theirrespective pointers 35, 91 by clutches 39, 1 I. It is desirable to fixthe pointers in a definite position during the periods when the clutchesare disengaging and it is necessary that the clutches be of the positiveposition type. One suitable form of clutch is shown in Figs. 3A and 3B.The movable portion of the clutch IdI is slidably connected to the motorshaft |63 by means of splines or other suitable means to preventrelative rotation. The movable portion of the clutch includes a biasingspring |35 which may be arranged to disengage the clutch. The solenoidwinding Ill1 is arranged to attract the armature whereby the cam surfaceof the clutch is The cam follower is mounted on a shaft III whichcarries an indicator or pointer I3 which corresponds to one of thepointers 95, 91. The shaft III is arranged to rotate freely during theclutch engagement. When the clutch is disengaged, a biasing spring I I5applies a brake to lock the pointer l I3 in position.

The operation of the foregoing instrument is essentially as follows: Theradio receiver l, being tuned to a transmitter operating on onefrequency, causes the differential relay 1 to engage either the upper I9or the lower -contact 2| if the loop is not properly orientedWithrespect to the direction and sense of the transmitting station. Suchengagement. will drive the impulse motor 21 clockwise orcounter-clockwise, as the case may be, thereby orienting the loop 5 tothe radio heading of the transmitter. The pulses which operate the looporienting motor 21 are also applied to the repeater motors 29, |23 andto the pointer motors 65, 61 so that the armatures .0f vBach of thesemotors operate in synchronism with respect to each pulse applied duringthe contacting of the differential relay 1. If no other impulses wereapplied, the five motors 21, 29, 85, 51 would be operated in synchronismand their armatures would adopt positions corresponding to the loopposition, which indicates the radio heading.

The orientation or heading of the earth com pass, with respect to thefollow-up or ,repeater mechanism, is caused by this mechanism to actuatethe differential relay tl. If the current in the differential relay isnot Zero, one i5 or the other 55 of the differential relay contacts'will be connected so that pulses from the pulse generator are appliedto the motor 5|. Iihe armature of the motor will be driven clockwise orcounter-clockwise, as the case may be, so that the shaft 6I drives therepeater mechanism 39 until the mechanism .repeats the earth compassheading. The same pulses which are applied to the motor 5| are appliedto the repeater motor 53 and to the bearing indicator motors 53, 55, 51.

Thus it follows that pulses derived as a function of the radio compassheading and the earth compass heading are applied to the bearingindicating motors 53, 65, 31. rlhese pulses will cause the motors E3,|55, 61 to adopt armature positions which represent the algebraic sum ofthe radio heading and the earth heading, as described by reference toFig. l.

Since one of the clutches (3S or 1|) will be engaged immediately afterthe loop is oriented, its pointer or 91, as the case may be) will thenfollow the bearings indicated by its motor (either 55 or G1) When theloop is tuned to the other transmitter, the first-mentioned clutch willbe disengaged and then the three motors will be oriented to correspondto radio bearing of the second station and the pointer of the secondclutch will be oriented to the second radio bearing. In the meantime,the first-mentioned pointer remains locked in position corresponding tothe first bearing. It should. be understood that the alternate tuning'tothe two transmitting stations is accomplished at a rate which permitsthe loop to become oriented to indicate the bearing of first one andthen the other of the stations.

If a single bearing indication is required, it should be understood thata single tuning may be used and the pair of clutches may be omitted. Therepeater motors 29, 53 and 63 are'not essential to the invention, butare considered desirable to provide for unitary and remote indicationsof the earth heading (H), radio heading (R) and bearing (Bi).

If a pair of pointers are used, it is possible to automatically anddirectly indicate position by utilizing the arrangement, for example, ofFig. 4. A map II1 is fastened to a suitable support. The axes IIB, |2|of the pointers |23, |25 are set to correspond to the respectivetransmitter locations. The pointers |23, |25, corresponding to thepointers 95, 91, are oriented by the bearing motors and clutches aspreviously described, whereby each pointer or indicator assumes aposition corresponding to the bearing of the respective stations. Theintersection of the bearing lines is the position of the instrument.Since the bearings (B) are obtained without reference to the course ofthe craft, it follows that a change in the course will not affect theposition indication on the map of Fig. 4.

In Figs. 5 and 6 the forego-ing arrangement has been modified toeliminate the clutches. In the modified arrangement of Fig. 5, a pair ofcommutator devices |53 are mechanically coupled by rotating shaft or thelike to the motor |55, which orients the loop |51. Since the commutatordevices are identical and differ only in that one responds to one radiochannel, while the other responds to a different radio channel, a singledescription will suflice.

The pulse generator |59 is connected through an element of the switchIBI to a slip ring connection |63 on, the commutator |5I. Approximately180 of the commutator is insulated |65. An insulated yoke |61 carriesbrushes |69, |1| which engage the commutator in the portion whichincludes insulation and conductive material. The yoke |61 is connectedto the armature of a follower motor |13. The brushes |69, |1| areconnected to the eld coils, forward and reverse, |15, |11 of thefollower motor, to the corresponding eld coils of a repeater motor |19,to the field coils of a radio bearing indicator motor |8|, and to thefield coils of a radio bearing repeater motor |93.

An earth compass |85, repeater drive mechanism |81, differential relay|89, and follower motor |9| are connected as previously described. Thefollower motor is also connected to a compass heading repeater motor 93.The field terminals of the compass heading repeater motor are connectedto the movable contacts of a. switch |95. Two of the fixed contacts ofthis switch |95 are connected to the repeater motor |83 and bearingmotors IBI, whereby these motors will respond to the algebraic sum ofthe pulses applied thereto. It should be understood that the secondchannel includes the commutator device |53, radio heading repeater motor|91, radio bearing repeater motors |99 and 20|. The compass circuit isapplied to the second channel by means of the switch |95, while impulsepower is simultaneously supplied thereto by means of the switch |6|.

The radio compass receiver includes a switch 203 which is connected to apair of tuning elements 205, 201. The switches IEI, |95 and 203 areoperated in synchronism whereby rst one channel and then the otherchannel for indicating and repeating radio bearings is energized. Thesynchronously operated switches may be driven by a motor 209 at a speedwhich is sufciently slow to enable the loop to orient itself withrespect to each of the desired transmitting stations.

The operation of the foregoing instrument is essentially as follows:Assuming that one radio channel is energized, the loop will be orientedto indicate the radio heading as a function of the transmitter inquestion. 'I'his orientation of the loop kwill crient the commutator|5|. The follower motor |13 will then be energized from a connectionthrough the commutator to the pulse generator whereby the follower motoris progressively driven clockwise or counter-clockwise, as the case maybe, until the brushes |69, |1| reach the insulated portion |65 of thecommutator, at which time no further pulses will be applied to thefollower motor. Since the repeater motors |19 and |93 and the bearingindicator motor |8| are all connected to the follower motor, theirrespective armatures will operate in synchronism with the follower motorand will take the same positions so far as the application of pulsesderived as a function of the radio heading is concerned.

The earth compass heading operates the follower motor |9I and the earthcompass heading motor |93 as previously described and, at the same time,the pulses which are derived vas a function of the earth compass headingare applied to the radio bearing motor |8| and the radio bearingrepeater motor |83. In this manner, a pointer 209 attached to the radiobearing motor |8| will indicate the radio bearing in terms of ameridian, as previously explained.

In a like fashion, the seco-nd channel indicates the radio bearing andradio heading by means of the motors |99 and 20|, and |91, respectively.It should be understood that the five motors |19, |93, |93, |91 and |99are repeater motors which are used only for remote indications. Theremote indicators include two radio headings, two radio bearings and anearth heading.

In Fig. 6, a somewhat different arrangement is used. In this instrument,the radio compass orienting motor 2|| and the earth compass followingmotor I3 are connected respectively to a third motor 2|5. The armatureof the third motor responds to the algebraic sum of the impulses appliedto the radio compass orienting motor and to the earth compass motor. Inother words, the armature of the third motor 2|5 assumes a positioncorresponding to the radio bearing referred to a meridian. The armatureof the third motor is connected mechanically to a pair of commutatordevices 2|1, 2I9 which are similar to the commutator devices previouslydescribed in connection with Fig. 5.

The slip ring connections 22|, 223 of the commutators are connectedrespectively to the fixed terminals of a two-position switch 225. 'Ihetwo-position switch is operated by a. motor 221 which also controlssynchronously a second twoposition switch 229. The fixed terminals ofthe second switch are connected to tuning elements 23|, 233 whichregulate the tuning of the radio receiver 235. The switch 225 appliesenergy from the pulse generator 231 to rst one and then the other of thecommutator devices 2|1, 2|9. The rate of the application of this energyis sufiiciently slow to permit the loop to orient alternately withrespect to a pair of transmitters radiating waves of differentfrequencies.

The energy from the pulse generator is applied to follower motors 239,24| which drive the brushes of the commutator devices to a positionwhich disconnects the commutators from the pulse generator. The samepulses which energize the follower motors also energize the radiobearing repeater motors 243, 245 which are connected in series with thefield windings of the follower motors. The armatures of the repeatermotors 243, 245 preferably include pointers 241, 249 which indicate,respectively, the two orientations of the loop.

If the pointers of the radio bearing repeater motors are arranged on a.map so that their axes correspond to the transmitting stations, theintersection of the pointers will indicate position irrespective of theorientation of the map. It should be understood that additional repeatermotors may be used to provide remote indications of the radio heading,earth heading and radio bearings.

Thus, the invention has been described as a navigation instrument inwhich indications of earth and radio headings are obtained and combinedto indicate a radio bearing with respect to a meridian. It should beunderstood that the invention is not to be limited to any particularform of self-orienting radio compass. Since the details of the radioreceiver are not part of this invention, no detailed description hasbeen given.

A description of a self-orienting radio compass is disclosed in thecopending application of Bond and Carlson, Serial No. 196,817, filedMarch 19, 1938, entitled finder.

I claim as my invention.:

l. A navigation instrument including, in combination, a radio compass, aservo motor device connected to the output of said compass for effectingself-orientation, an earth compass, a servo motor device connected tosaid earth compass for following its indications, means for applyingdriving pulses to each of said servo motor devices, and a motorresponsive to said applied driving pulses for combining said pulses toindicate a bearing as a function of the heading indications of saidradio and earth compasses.

2. A navigation instrumentl including, in combination, a -self-orientingradio compass, a pulse driven servo motor for effecting said orientationcoupledrto said radio compass, an earth compass, a second pulse drivenservo motor for following the heading indication of said earth compass,a source of pulse energy for said motors, and a third pulse driven motorresponsive to the sum of the pulses applied to said motors forindicating a bearing as a function of said radio compass orientation andsaid earth compass heading.

3. A navigation instrument of the character of claim l including meansfor alternately tuning said radio compass to a pair of transmittingstations, and means operated in synchronism with said alternate tuningmeans for alternately indicating the bearings of said instrument fromsaid transmitting stations.

4. A navigation instrument of the character of claim 2 including meansfor alternately tuning said radio compass to a pair of transmittingstations operating on different frequencies, and means operated insynchronism with said alternate tuning means for alternately indicatingthe respective bearings of said instrument from said transmittingstations.

5. A navigation instrument including, in combination, a self-orientingradio compass, a pulse driven servo motor for effecting said orientationcoupled to said radio compass, an earth compass, a second pulse drivenservo motor for following the heading indications of said earth compass,a source of pulse energy for said motors, a third pulse driven motorresponsive to the sum of the pulses applied to said motors forindicating a bearing as a function of said radio compass orientation andsaid earth compass heading, means for alternately tuning said radiocompass to a pair of transmitting stations operating on differontfrequencies, means operated in synchronism with said alternate tuningmeans for alternately indicating the respective bearings of saidstations, a map, and means for applying said last-mentioned bearingindication to said map to indicate position.

6. A navigation instrument including a selforienting radio compass,electric motor means for following said radio compass orientation, anearth compass, electric motor means for following the headingindications of said earth compass, a power source for said motors, andan electric motor responsive to forces driving each of said followingmeans for combining said forces to indicate a bearing as a function ofthe earth compass heading and the radio compass orientation.

Self-orienting radio direction 7. In a navigation instrument of thecharacter of claim 6, means for tuning said radio compass to a pair ofdifferent frequencies whereby said radio compass may be orientedalternately to a pair of positions, a second electric motor means forfollowing the second of said orientations, means for alternatelyenergizing said orientation following means, and a second meansresponsive to forces driving said second following means and to forcesdriving said earth compass following means for indicating a secondbearing as a function of the earth compass heading and the second ofsaid radio compass orientations.

8. A navigation instrument including a selforienting radio compass, anelectric motor for following said radio compass orientation, an earthcompass, a second electric motor for following the heading indicationsof said earth compass, means responsive to forces driving each of saidelectric motors for indicating a bearing as a function of the earthcompass heading and the radio compass orientation, means for tuning saidradio compass to a pair of different frequencies whereby said compassmay be oriented alternately to a first and a second position, a thirdelectric motor for following the second of said positions, means foralternately energizing said orientation following means, a second' meansresponsive to forces driving said third electric motor and to forcesdriving said earth compass following motor for indicating a secondbearing as a function of the earth compass heading and the second ofsaid radio compass orientations, a map, and means for applying saidfirst-named and said second bearing indications to said map to indicateposition.

9. A navigation instrument including, in combination, a self-orientingradio compass, an irnpulse motor responsive to the orientation of saidradio compass for indicating said orientation, an earth compass, animpulse motor responsive to the heading of said earth compass forindicating said heading, a source of power for said motors, impulsemotor means responsive to the forces actuating said first andsecond-mentioned impulse motors for combining said forces to indicate abearing as a function of said orientation and said compass heading, anda fourth impulse motor responsive to the combined forces applied to saidthird mentioned motor for repeating said lastmentioned bearingindication.

1G. A navigation instrument including, in cornliination, aself-orienting radio compass, means electrically driven and responsiveto the orientation of said radio compass to indicate said orientation,an earth compass, means electrically driven and responsive to theheading of said earth compass to indicate said heading, a source ofelectric power for said electrically driven means, means responsive tothe electrical power driving the rst and second-mentioned responsivemeans to indicate a bearing as a function of said orientation and saidcompass heading, means for tuning said radio compass to two frequenciesso that said compass may be alternately oriented to two positions, asecond means electrically driven and 'responsive to the second of saidoriented positions and to said earth compass orientation for indicatinga second bearing, means operated in synchronism with said alternatetuning for alternately indicating bearings, a map, and means forapplying said alternately indicated bearings to said map to indicateposition.

DAVID G. C.I LUCK.

